Domino R6 on SuSE 8.1 - Installation - DISPLAY environment

Hello,

after installing Domino R6 
/opt/lotus/bin/http httsetup
exits with the error:

""Please edit your shell's DISPLAY environment variable to
reflect an unlocked terminal that you would like to launch
the Domino Setup Program""

The system is a standard Suse 8.1 installation. 
Nothings has been changed despite of that I installed:
RPM resource libstdc++-libc6.1-1.so.2 for Suse, which
soluted the installation error before.

Thanks - Stephan